Describir: Design of prestressed concrete beams :

 _    _      ___      ______     ___     _____       ___      ______  
| || | ||   / _ \\   /_   _//   / _ \\  |  __ \\    / _ \\   /_   _// 
| || | ||  | / \ ||  `-| |,-   / //\ \\ | |  \ ||  / //\ \\  `-| |,-  
| \\_/ ||  | \_/ ||    | ||   |  ___  ||| |__/ || |  ___  ||   | ||   
 \____//    \___//     |_||   |_||  |_|||_____//  |_||  |_||   |_||   
  `---`     `---`      `-`'   `-`   `-`  -----`   `-`   `-`    `-`'   
                                                                      
  ______  
 /_   _// 
  -| ||-  
  _| ||_  
 /_____// 
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